There is a desire to enjoy engine sound (exhaust sound) during driving of an automobile. Patent Literature 1 proposes a technique of outputting, from a speaker in an automobile, a pseudo engine sound (pseudo exhaust sound) in accordance with a desire of a driver of the automobile, thereby providing acceleration feeling to the driver.
Also, Patent Literature 2 proposes a technique of dividing the engine driving state into multiple areas with an accelerator position and an engine rotation speed of an automobile as parameters, storing, as digital data (sound source data), an actual engine sound recorded in the state substantially at a center of each of the multiple areas, and providing engine sounds of the stored digital data to an interior of the automobile.
Also, Patent Literature 3 proposes a pseudo sound providing system including storage means for storing a sound source and effect data that affects the sound source, generation means for generating pseudo engine sound data by applying an effect based on the effect data corresponding to driving state data to the sound source, and reproduction means for outputting a pseudo engine sound based on the generated data.